The reaction of uranium hexafluoride (UF.sub.6) with steam to produce uranyl fluoride (UO.sub.2 F.sub.2) is well known. The defluorination/reduction of uranyl fluoride with steam and hydrogen to produce uranium dioxide of low fluoride content also is well known. Various types of reactors and rotary kilns have been employed in sequentially carrying out the so-called dry conversion of uranium hexafluoride to uranyl fluoride and the subsequent defluorination and reduction of uranyl fluoride to uranium dioxide (UO.sub.2).
Representative of processes for the conversion of uranium hexafluoride to uranium dioxide in furnaces and rotary kilns and the like are the following: U.S. Pat. No. 3,168,369; U.S. Pat. No. 3,260,575; U.S. Pat. No. 3,235,327; U.S. Pat. No. 3,845,193; U.S. Pat. No. 4,112,055 and U.S. Pat. No. 4,397,824.
Representative examples of processes in which the conversion is carried out in one or more fluid beds can be found in U.S. Pat. No. 3,547,598; U.S. Pat. No. 3,765,844; U.S. Pat. No. 3,978,194; U.S. Pat. No. 4,020,146; U.S. Pat. No. 4,053,559 to mention a few.
The deficiencies of the foregoing processes are well known. For example, in some instances the throughput rate is limited by the defluorination rate of UO.sub.2 F.sub.2. In other instances, the UO.sub.2 F.sub.2 powder obtained is very fine, has poor flow characteristics, is ceramically inactive and requires milling, high pressing pressures and a binder for pelletizing. In yet other processes, the use of multiple complex reactors increases the difficulty to control the process as well as increases the cost associated with producing the desired uranium dioxide. Indeed, the very number of processes disclosed is testimony to the continuing need for a new and an improved process for the conversion of uranium hexafluoride to uranium dioxide.